Clothes Washers - water temp effects on stain removal
This article outlines some of the effects of water temperature on cleaning performance in a clothes washer - specifically, the removal of various types of stains. The experimental data below serves to illustrate the importance of proper water temp, and one of the advantages of having an internal heater in a clothes washer (that can reach these "very high" wash temps). [See also the related FAQ article, "Clothes Washers - Internal Heater Advantages ??".] This is a simple test, washing various "tough" stains with a measured dose of a given detergent and no pre-treatment.
[Report first posted in the Appliances Forum by Alice (Alice_61) on 22 September 2002 in the "Technical Suds Part 2" thread - thanks, Alice!]:
The effect of temperature on stain removal in the Miele W1918A washer
I washed a stain strip with a 10 lb. load of cottons and 2 oz (by weight) of Tide HE powder in the Intensive Cotton cycle, using each of the available temperatures on the Miele W1918A: 85F (30C), 105F (40C), 120F (50C), 140F (60C), 155F (70C), 180F (80C), and 190F (90C).
First, a few general comments before I get into the particulars of specific stains:
1. Before these stain tests, I had choosen wash temperatues strictly according to the user's guide. Because we have so few whites, I had never done a wash above 140F. I was willing to go to higher temperatures with the test load, because it consisted of old clothes and rag material. After trying the 190F wash, I was very impressed at how colorfast most items were. There were a couple of things that colored the drain water (colored jeans), so I replaced them with other items for the test load.
2. The white background of the stain swatches was much whiter at the higher wash temperatures. This didn't become too noticable until 155F, and increased to a very bright white at 190F. It seems from this and the better stain removal of certain stains, that the bleach was becoming more active at higher temperatures.
3. I used some old, cheap (the 12/$3.00 type) wash clothes for the test load. We had gotten to the point of using them as cleaning clothes. After about 25 washings with the test load, many at high temperatures and some with considerable detergent doses, these wash clothes were very clean and bright. I happened to find some identical wash clothes stashed away and compared them to these very washed ones. Not only were the very washed ones much cleaner and brighter than the old ones, they did not seem any more faded than the old ones. In fact, they looked a whole lot better. Perhaps greying of the old washclothes made them seem less colored. I think this and #1 alleviates my concern about fading at high temperatures, at least for colorfast items.
4. The detergent perfume smell is considerably reduced by washing at high temperature. I didn't really notice this until the last two loads (180 and 190F) so I can't say exactly at which temperature this occured.